Roles of Promoter and Support of Sulfided Mo-based Catalyst in Selective Hydrotreating of Palm Fatty Acid Distillate

A series of CoMo/Al2O3 catalysts with various Co/Mo mole ratios and a series of CoMo/TiO2–Al2O3 catalysts supported on TiO2 coating Al2O3 were prepared. The effects of Co/Mo mole ratio and TiO2 loadings on Al2O3 on hydrodeoxygenation (HDO) and decarboxylation/decarbonylation (DCO) in the hydrotreating of palm fatty acid distillate (PFAD) were investigated. The catalysts were characterized by BET, XRF, pulse NO chemisorption, and H2-TPR. The maximum yields of n-C16 and n-C18 was observed at Co/Mo = 0.05 for the CoMo/Al2O3 series, and the yield of n-C15 and n-C17 was increased at Co/Mo > 0.05. CoMoS phase apparently has both HDO and DCO activities. CoMo(0.05)/Ti(20)–Al showed the maximum yields of n-C16 and n-C18 due to the formation of TiMoS in all catalysts. TiMoS phase may be formed by adding TiO2 on Al2O3 and promotes the HDO reaction, but not isomerization or cracking.